#include<fstream.h>

long long n, p;

int prim(long x,long y)
{
  while (x!=y)
    {
      if (x>y) x=x-y;
	else y-=x;
    }
  if (x==1) return 1;
  return 0;
}

void calcul()
{
  long long nr, contor=0;
  ifstream in("frac.in");
  in>>n>>p;
  nr=0;
  while (contor<p)
   {
     nr++;
     if (n%2==0 && nr%2==0);
	else	if (prim(n,nr)) contor++;
    }
  ofstream out("frac.out");
  out<<nr;
  in.close();
  out.close();
}

int main()
{
  calcul();
  return 0;
}